More US residents are dependent on marijuana than on any other illicit drug, and the number enrolled in treatment for marijuana continues to increase such that it is now comparable to that for cocaine and heroin. This application seeks to advance our overarching goal to develop and disseminate cost-effective treatments for marijuana dependence that can address this growing problem. Our previous research suggests that an intervention comprising motivational enhancement, cognitive-behavioral, and contingency-management components (MET/CBT/CM) produces greater rates of successful and durable outcomes than has been demonstrated previously. However, three issues relevant to its efficacy and eventual dissemination must be confronted. First, the outcomes achieved can only be characterized as modest;many individuals do not respond to the treatment and relapse rates remain problematic. Second, access is limited by the availability of trained providers. Third, the cost of delivering the treatment is higher than more traditional outpatient interventions. To address these issues, Specific Aim 1 is to develop and test a computer-assisted version of MET/CBT/CM. Computerized treatments have the potential to increase overall effectiveness of treatment services by increasing availability of and access to potent treatments, and by applying innovative technology to enhance outcomes. During Year 1, the intervention will be developed and pilot tested. An interactive program that showed promise in our previous trial for opioid dependence will be modified and enhanced to deliver individualized MET/CBT/CM using effective computer learning technologies. These technologies and access to the MET/CBT/CM program made available via the Internet between treatment sessions and after treatment ends have the potential to promote better learning and more use of coping skills, which in turn can improve outcomes. During Years 2-4 a randomized trial will provide an initial efficacy test of cMET/CBT/CM by comparing it with a brief treatment (MET) and with therapist-delivered MET/CBT/CM. Specific Aim 2 is to learn more about how behavioral treatments like MET/CBT/CM work by focusing on two putative mechanisms of action examined in prior trials: self-efficacy/coping skills and impulsivity/delay discounting. The experimental design will provide a unique opportunity to explore such mechanisms in a novel context- where the therapist is vs. is not a prominent part of the treatment. The proposed project will address the objectives of NIDA's Behavioral and Integrative Treatment Development Program by providing research on technology-assisted treatment that attempts to make treatment delivery less complex, easier to access, and less costly - while retaining or improving its effectiveness. Findings will inform future studies designed to refine the technology and how it is applied;conduct more definitive effectiveness testing;test generality to other populations including adolescents;and to further advance translation to community settings.